532 THE ANIMAL PARASITES OF MAN 



(6) Diptera. Two membranous wings only ; mouth suctorial, very varied ;: 



metamorphosis complete. 



(7) Lepidoptera. Four large wings covered with scales : mouth suctorial^ 



metamorphosis great. 



(8) Hymenoptera.o\\r membranous wings ; front pair larger than hind, which 



do not fold up in repose ; mandibulate, sometimes with a tubular 

 proboscis ; metamorphosis complete. 



(9) Coleoptera. Four wings, the front pair hard and horny (elytra), meeting in 



a line over the back and covering the delicate hind pair ; mandibulate ; 

 metamorphosis complete. 



[There are two other well-known arrangements, namely, Packard's and Brauer's, 

 of recent date, but the one given here, which is based on Linnaeus' 

 grouping by Dr. Sharp, is by far the simplest. F. V. T.J 



Order. Rhyncota. 1 



The lower lip forms a long thin tube that can be turned back (rostrum), and 

 within which lie the setaceous mandibles and maxillae; the first thoracic segment is 

 not united with the two posterior ones ; the anterior wings are usually leathery as 

 far as the centre. 



(a) RHYNCOTA APTERA PARASITICA. 



Family. Pediculidae (Lice). 



The lower lip is transformed into a projecting rostrum provided with barbed 

 booklets in which the hollow extensile sucker (maxillae and mandibles) is situated ; 

 no wings ; no metamorphosis ; only simple eyes ; the antennae are five-jointed, 

 the feet possess hook-like terminal structures ; the barrel-shaped eggs (nits) are 

 deposited on the hair of the host. 



[The lice or Pediculidce are also known as Anoplura and Siphunculata. 



[They have been split up into a number of families and sub-families and a 

 number of genera, but as far as this work is concerned it is best to retain the single 

 family PediculidcE. 



[Only the three species mentioned here are common parasites of man, but now 

 and then horse and cattle and sheep lice, Htzmatopinus, may cause transitory 

 annoyance. F. V. T.] 



Genus. Pediculus, Linnaeus. 

 Pediculus capitis, de Geer, 1778. 



Male i to 1-5 mm. in length, female r8 to 2-0 mm. in length. 

 The colour varies from light grey to black according to the colour of 

 the hair of the human race upon which they are parasitic. The 

 abdomen has eight segments, of which the six central ones are 



1 [Usually known as Hemiptera. There are two sub-orders, Heteroptera and Homoptera. 

 The former have the base of the front wings coriaceous ; the latter have all four wings 

 membranous. The Homoptera are Aphides or plant lice and scale insects (Cocdi/a), none 

 of which attack man. Recently an interesting case has been reported to me where certain 

 Aphides had been passed in human urine. One species was Rhopalosiphttm dianthi, the 

 other found in the urine was the hop aphis (Phorodon humuli). I cannot believe, however, 

 that they had been actually passed, in spite of the case being reported by a medical man. 



